Preschool children's moderate-to-vigorous-activity cut-points: Comparison between cutpoints based on vector magnitude and X-axis cut-points

Abstract: The movement of preschool children happens on several planes more often compared school-aged children or adults. The accelerometers, such as Actigraphs, are used for measuring children’s moderate-to-vigorous activity (MVPA), and the current models of accelerometers allow measuring movement on three different axis. To our knowledge, there is currently only one validated cut-point values for preschool children based on the vector magnitude calculations (Butte’s vector magnitude (VM) cut-points). This study aimed to compare the MVPA minutes according to VM and x-axis cutpoints. A pilot study of the DAGIS project was conducted in 2014. The 3-6 years old children (N=23) wore accelerometers (Actigraph wGTX3-BT) (approx. 3 hours 30 minutes without naps) in preschool. The children had a physical activity lesson during the day. The Butte’s VM cut-point of MVPA (>6112counts per minute, cpm) were compared to Sirard’s (>2457cpm), Evenson’s (>2296cpm), Pate’s (>1680cpm), and Butte’s x-axis cut-points (>2120cpm). The mean minutes of MVPA according to Butte’s VM cut-points were 29 minutes.The other mean minutes were 22, 24, 36 and 28, respectively. According to Friedman’s repeated measures ANOVA, there was a statistically significant difference in MVPA depending on the cut-points, χ2(4) = 79.527, p = 0.000. Pairwise comparisons showed that the Butte’s VM minutes for MVPA differed to Evenson’s, Pate’s and Sirard’s minutes. No significant difference was found between Butte’s VM and Butte’s x-axis cut-points. To conclude, there was variation in MVPA minutes between used cut-points. The consensus about proper cutpoints should be achieved, which helps to design proper MVPA recommendations.